"Percy Jackson is about to be kicked out of boarding school...again. And that's the least of his troubles. Lately, mythological monsters and the gods of Mount Olympus seem to be walking straight out of the pages of Percy's Greek mythology textbook and into his life. And worse, he's angered a few of them. Zeus's master lightning bolt has been stolen, and Percy is the prime suspect." -- from front jacket flap.

When the goddess Artemis disappears while hunting a rare, ancient monster, a group of her followers joins Percy and his friends in an attempt to find and rescue her before the winter solstice, when her influence is needed to sway the Olympian Council regarding the war with the Titans.

All year the half-bloods have been preparing for battle against the Titans. Now it's up to Percy Jackson and an army of young demi-gods to stop the Lord of Time.